掺uea水泥净浆膨胀与强度性能试验研究.docxVIP

掺UEA水泥净浆膨胀与强度性能试验研究 任朋勋1,2，张福海1,2 (1.河海大学 岩土工程科学研究所，江苏 南京210098 2.河海大学教育部堤坝与岩土工程重点试验室，江苏 南京 210098) 摘 要：本文以土钉钻孔注浆中的水泥净浆进行研究，以 UEA膨胀剂为膨胀源，通过水泥膨胀性试验与强度试验，研究 了不同膨胀剂掺量和不同水胶比对水泥净浆膨胀性能与强度的影响。研究结果表明：在 UEA掺量6%?10%、水胶比 0.38?0.48范围内，水泥净浆始终是膨胀的，膨胀率随 UEA掺量的增加而增加，随水胶比的增加而减小，当水胶比大于 0.42时，膨胀率将明显降低；净浆试件在内置钢筋条件下的限制膨胀率约为相同情况下自由膨胀率的一半； UEA有利于 普通硅酸盐水泥早期强度的发展，但对水泥的最终强度影响不大，且掺量不宜超过 10%。 关键词：水泥净浆；UEA膨胀剂；自由膨胀率；限制膨胀率 ；水泥强度 ［中图分类号］TU528 ［文献标识码］ A A Test study on expansion and strength properties of cement paste mixed with UEA 1,21 2 1,2 REN Peng-xun , , ZHANG Fu-hai 210098, China(1. Geotechnical Engineering Research Institute, Hohai University, Nanjing, Jiangsu 210098, China 2. Key Laboratory of Ministry of Education for Geo-mechanics and Embankment Engineering, Nanjing 210098, China) Abstract : This article studies the cement paste in grouting of soil nailing, UEA expansive as the source of expansion, by cement swelling and strength experiment research on free expansion, limit expansion and strength of cement paste with the dosage of UEA and different water-cement ratio. Research suggests in the range of the UEA content in 6%~10%, water cement ratio in 0.42~0.48, the cement paste is always expanding, expansion rate increases with the dosage of UEA and decreases with the increase of water cement ratio, expansion rate will sharply declined when the water cement ratio is greater than 0.42; The restricted expansion rate of cement paste specimens in the built-in reinforced is about half of the free expansion in the same situation; UEA is conductive to the development of Portland cemenfs early strength and have little effect on ultimate strength, and the quality of UEA do not added more than 10%. Key words: cement paste; United Expensing Agent; free expansion ratio; restricted expansion ratio; cement strength 1引言 土钉支护因其经济可靠，快捷简便的特性，近 年来发展迅速，被广泛应用于基坑支护、边坡支护 等工程中，也常常与其他桩体或支护形式组合使 用。水泥净浆与水泥砂浆常被用于土钉支护中钻孔 的注浆，为保证注浆材料对钻孔的充分填充与防止 注浆体在硬化过程中产生干缩裂缝，常要求水泥注 浆材料不发生体积收缩［1］。并且在工程应用中也常 发生由于超挖，土钉的承载力发挥过晚等原因，导 致边坡